On behalf of @Whale and I:
Currently there is not much reason at all to level a townsfolk friendship to 99 other than museum completion or just completion, something that many people don't deem worth it and would rather focus on significant game progress.
To additionally add a friendship bracelet on top of the collectibles bobblehead, or even just apply this affect to bobbleheads, that provided a boost to PHR rewards from that specific townsfolk would give a meaningful reason to push for 99 friendships. It would give a reason to work on friendship at all as really the only reason currently in the game is for friendship locked quests, with very few existing in the first place and even fewer being mandatory or even remotely significant at the moment. Adding an effect like this would give an actually beneficial reason to not just get a few townsfolk to 99 after your first for the merit badge if you have a few super loves laying around, but to actively work on them all so that you can maximize any possible PHR reward you get daily.
